Wide-spectrum polarization-sensitive and fast-response photodetector based on 2D group IV-VI semiconductor tin selenide

Tin selenide (SnSe) has attracted considerable interest recently on account of its low-symmetry lattice structure, great compatibility with key semiconductor technology, and remarkable electrical and optical performance. SnSe-based polarization-sensitive photodetectors show promising application prospects because of their fast response and excellent photoelectric performance. Here, an in-plane anisotropic SnSe nanosheet was synthesized and reported in detail by applying angle-resolved polarized Raman spectroscopy (ARPRS), polarization-resolved optical microscopy(PROM), angle-resolved optical absorption spectroscopy (AROAS), and other crystal structure characterization methods. Moreover, SnSe crystals exhibit superior polarization detection performance with a high anisotropic photocurrent ratio (2.31 at 1064 nm) due to the structure formed by the Van der Waals superposition of covalently bonded atomic layers. Furthermore, SnSe-based photodetectors have high responsivity (9.27 A/W), high detectivity (4.08 × 1010 Jones), and fast response (in the order of nanoseconds). These results suggest a new method for fabricating 2D fast-response polarization-sensitive photodetectors in the future.